The Physical Universe
An Introduction to
Astronomy

Frank H. Shu
University of California, Berkeley

Color Plates from the First
Printing

Most of the images may
be viewed in a larger size by clicking on the thumbnail

Color Plate 1. An eruption 365,000 miles across on the Sun recorded by
Skylab in the 304 Å ultraviolet light of ionized helium. (NASA and the
Naval Research Laboratory.)

Color Plate 2. A spectrum of the day sky which constitutes scattered
sunlight. The continuum from violet to red has superimposed on it dark
absorption lines which are formed in the atmosphere of the Sun.

Color
Plate 3. Messier 16, the Eagle nebula in Serpens, containing an open
cluster of stars. (Copyright Association of Universities for Research in
Astronomy, Inc., The Kitt Peak National Observatory.)

Color Plate 9. Messier 31, the Great Galaxy in Andromeda, the closest
large spiral galaxy to our own. (Palomar Observatory photograph, copyright by the
California Institute of Technology.)

Color Plate 10. Messier 32, a dwarf elliptical
galaxy in the Local Group of galaxies. (U.S. Naval Observatory.)

Color Plate 11. NGC5128, a peculiar
elliptical galaxy in Centaurus; it is a source of intense radio
emission. (Copyright Association of Universities for Research in
Astronomy, Inc. The Cerro Tololo Inter-American Observatory, CTIO
4-meter photograph.)

Color Plate 13. Messier 51, The Whirlpool Galaxy, a
spiral galaxy in Canes Venatici seen nearly face-on. It has a
companion galaxy at the projection of one of its spiral arms.
(U.S. Naval Observatory.)

Color Plate 17. A panoramic view of the Martian
landscape taken by the Viking 1 lander. Notice the trench on the
lower right which was dug so that, among other experiments, the lander
could test the Martian soil for possible biological activity. (NASA)

Color Plate 18. A closeup view of the turbulence in
Jupiter's atmosphere taken by Voyager 1. (NASA, Jet Propulsion
Laboratory.)

Color Plate 19. Huge volcanic eruptions were
discovered by Voyager 1 on Io, one of the moons of Jupiter. (NASA,
Jet Propulsion Laboratory.)

Color Plate 20. A thick
haze covers the
surface of Titan, the largest moon of Saturn. Detailed analysis of
Voyager 1 data revealed surprisingly that Titan's atmosphere was made
mostly of molecular nitrogen, with a surface pressure somewhat larger
than that of Earth and a surface temperature cold enough possibly to
allow pools of liquid nitrogen in special locations. (NASA, Jet
Propulsion Laboratory.)

Color Plate 21. An unusual comet, Comet Humason.
If funding can be found, scientists hope to fly a spacecraft in 1986 for
a much closer view of Halley's comet. (Palomar Observatory
photograph, copyright by the California Institute of Technology.)

Color Plate 22. A false-color X-ray image of the
quasar OQ 172, which has the highest redshift, 3.53, yet known.
(NASA, courtesy of William Ku and Columbia University.)

Color Plate 23. The double quasar. The left
side of the image gives a false-color view of the system; the right side
shows an imaged processed view after subtraction to reveal the presence
of the intervening galaxy which presumably acts as the gravitational
lens. For details, see A. Stockton, Ap. J. Lett., 242, 1980, L141,
and Chapter 15. (Institute for Astronomy and Planetary Geosciences
Data-Processing Facility, University of Hawaii.)

Color Plate 24. A radiograph of M101 showing
the distribution and velocity of atomic hydrogen in this Sc I
galaxy. Red denotes redshifts with respect to the center of the
galaxy; blue, blueshifts. (Kepteyn Astronomical Institute,
University of Groningen and the Netherlands Foundation for Radio
Astronomy; courtesy of Ronald J. Allen.)

Color Plate 25. A false-color radiograph
showing the distribution of atomic hydrogen gas in the spiral galaxy
M81, the small irregular galaxy NGC 3077, and the streamer that connects
the pair. In this representation, green refers to the highest
intensity of the neutral hydrogen emission. (Kapteyn Astronomical
Institute, University of Groningen and the Netherlands Foundation for
Radio Astronomy; courtesy of Ronald J. Allen.)

Color Plate 27. Messier 33, the third largest
spiral galaxy in the Local Group after the Milky Way and M31. (Palomar Observatory
photograph, copyright by the California Institute of Technology.)

Color Plate 28. The central bulge of M31. (Copyright Association of Universities for Research in
Astronomy, Inc. The Kitt Peak National Observatory.)

Color Plate 29. The Large Magellanic Cloud, a
barred irregular galaxy which is a satellite of the Milky Way System. (Copyright Association of Universities for Research in
Astronomy, Inc. The Cerro Tololo Inter-American Observatory, CTIO
61-cm Schmidt photograph.)

Color Plate 30.
Radiograph showing the
distribution and velocity of atomic hydrogen gas present locally in our
Galaxy. (Courtesy of Carl Heiles and the Radio-Astronomy
Laboratory, University of California, Berkeley.)

Color Plate 31. A relatively wide-angle view
of a portion of our Galaxy that includes the Horsehead nebula. (Palomar Observatory
photograph, copyright by the California Institute of Technology.)

Color Plate 32A.. The old and the new.
The stars in the globular cluster Omega Centauri, NGC 5139 (Plate 32A)
are over ten billion years old. Contrast with Plate 32B, below,
showing stars in the open cluster NGC 6231, which are relatively newly
born from the surrounding gas and dust. (Copyright Hans
Vehrenberg)

Color Plate 44. A
two-color picture of Deimos, the smaller of the two satellites of Mars,
generated from Viking 1 camera shots through a violet filter and an
orange filter. Deimos is believed to resemble most common
asteroids. (NASA).

Color Plate 45. View of the
area near the Viking 1 Lander site on Mars. (NASA).

Color Plate 46. Frosty scene
near the north pole of Mars viewed in mid-summer by Viking Orbiter 2.
(NASA).

Color Plate 47. Four
false-color ultraviolet views of Venus by Pioneer Venus Orbiter.
The time sequence begins clockwise from lower left, and shows that the
planet's clouds circle Venus completely once every four days, much
faster than the rotation period of the planet. (NASA, Ames
Research Center).

Color Plate 48.
Eruption of the Sun viewed from Skylab at 304 Å. (NASA and the
Naval Research Laboratory.)